Diamonds are the hardest known substance found in nature. Diamond is defined as a mineral composed entirely of the allotropic form of the element carbon, crystallized in the isometric system, and covalently bound by single bonds in tetrahedral fashion. Diamond also has the highest thermal conductivity of any known substance which, at room temperature, is approximately five times the thermal conductivity of copper. Because of this high thermal conductivity, diamonds used in cutting tools do not become hot, a quality which contributes greatly to their usefulness and desirability in such applications.
Man-Made diamonds were first successfully synthesized by the General Electric Company in 1955. Since then, diamond has been synthesized in a number of ways, but all of which require application of extremely high temperatures and external pressures. The typical methods include static crystallization from molten metals or alloys at pressures of 50 or more kilobars and temperatures greater than 1500.degree. K. (2240.degree. F.); shock conversion from graphite at pressures of about 300 kilobars and temperatures of about 1300.degree. K. (1880.degree. F.); and by static conversion from graphite at pressures of more than about 130 kilobars and transient temperatures more than about 3300.degree. K. (5480.degree. F.).
With these general techniques as background, it becomes evident that any method of forming diamonds synthetically that can be carried out at more moderate temperatures and externally applied pressures or, indeed, in the absence of extreme temperatures or externally applied pressures would provide a tremendous advance in the production and use of synthetic diamonds.
As set forth in application No. 07/816,636 set forth above ("the '636 application"), "fullerenes" is a term given to a recently postulated and discovered form of molecular carbon in which the carbon atoms are joined to form spheres, or sphere-like structures. Because of the resemblance between the structure of these molecules and the geodesic domes designed and championed by the architect, Buckminster Fuller, such molecules have been designated as "fullerenes," and the basic and most stable molecule, a sphere having 60 carbon atoms, has been designated "Buckminsterfullerene." For the same reasons, fullerenes have also been referred to as "buckyballs."
As further set forth in the '636 application, it has now been discovered that fullerene structures can be produced in metallic matrices, particularly in allotropic metals such as iron.